The two machines differ only in their choice of CPU. The MI640 nano has a four-core, eight-thread Core i5-8250U processor that boosts up to 3.4 GHz, while the MI660 nano's Core i7-8550U boosts to an even 4 GHz. The diminutive machines are fitted with two SODIMM slots ready to accept up to 32 GB of 2400 MT/s DDR4 memory and a single bay for a 2.5" SATA storage device. Curiously, there aren't any M.2 slots for adding NVMe devices.

The I/O section is sparse but modern with HDMI 2.0 and DisplayPort 1.2 jacks that can output 3840x2160 video signals at 60 Hz. Two Gigabit Ethernet connectors and four USB 3.0 Type-A ports also dot the back of the Zboxes. The front panel sports USB 3.0 Type-A and Type-C ports along with a card reader and audio jacks. Buyers can also connect the Zboxes to Bluetooth 4.2 devices and 802.11ac Wi-Fi networks without using wires.

All of the power and connectivity resides in a package measuring 5" wide, 5" deep, and 2" thick (13 cm x 13 cm x 5.1 cm). For those keeping score at home, that multiplies out to a scant 0.82 L. Zotac has yet to provide pricing or availability information for the Zbox MI640 nano and Zbox MI660 nano, though we imagine the diminutive machines will hit store shelves soon.